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<pre><code><span class="keyword">use</span> <span class="module crate_root library">proc_macros</span><span class="operator">::</span><span class="brace">{</span><span class="function library">mirror</span><span class="comma">,</span> <span class="function library">identity</span><span class="comma">,</span> <span class="derive library">DeriveIdentity</span><span class="brace">}</span><span class="semicolon">;</span>

<span class="proc_macro library">mirror</span><span class="macro_bang">!</span> <span class="brace">{</span>
    <span class="brace macro proc_macro">{</span>
        <span class="comma macro proc_macro">,</span><span class="builtin_type macro proc_macro">i32</span> <span class="colon macro proc_macro">:</span><span class="field declaration macro proc_macro public">x</span> <span class="keyword macro proc_macro">pub</span>
        <span class="comma macro proc_macro">,</span><span class="builtin_type macro proc_macro">i32</span> <span class="colon macro proc_macro">:</span><span class="field declaration macro proc_macro public">y</span> <span class="keyword macro proc_macro">pub</span>
    <span class="brace macro proc_macro">}</span> <span class="struct declaration macro proc_macro">Foo</span> <span class="keyword macro proc_macro">struct</span>
<span class="brace">}</span>
<span class="keyword">macro_rules</span><span class="macro_bang">!</span> <span class="macro declaration public">def_fn</span> <span class="brace">{</span>
    <span class="parenthesis">(</span><span class="punctuation">$</span><span class="parenthesis">(</span><span class="punctuation">$</span>tt<span class="colon">:</span>tt<span class="parenthesis">)</span><span class="punctuation">*</span><span class="parenthesis">)</span> <span class="operator">=</span><span class="operator">&gt;</span> <span class="brace">{</span><span class="punctuation">$</span><span class="parenthesis">(</span><span class="punctuation">$</span>tt<span class="parenthesis">)</span><span class="punctuation">*</span><span class="brace">}</span>
<span class="brace">}</span>

<span class="macro public">def_fn</span><span class="macro_bang">!</span> <span class="brace">{</span>
    <span class="keyword macro">fn</span> <span class="function declaration macro">bar</span><span class="parenthesis macro">(</span><span class="parenthesis macro">)</span> <span class="operator macro">-</span><span class="operator macro">&gt;</span> <span class="builtin_type macro">u32</span> <span class="brace macro">{</span>
        <span class="numeric_literal macro">100</span>
    <span class="brace macro">}</span>
<span class="brace">}</span>

<span class="keyword">macro_rules</span><span class="macro_bang">!</span> <span class="macro declaration public">dont_color_me_braces</span> <span class="brace">{</span>
    <span class="parenthesis">(</span><span class="parenthesis">)</span> <span class="operator">=</span><span class="operator">&gt;</span> <span class="brace">{</span><span class="numeric_literal">0</span><span class="brace">}</span>
<span class="brace">}</span>

<span class="keyword">macro_rules</span><span class="macro_bang">!</span> <span class="macro declaration public">noop</span> <span class="brace">{</span>
    <span class="parenthesis">(</span><span class="punctuation">$</span>expr<span class="colon">:</span>expr<span class="parenthesis">)</span> <span class="operator">=</span><span class="operator">&gt;</span> <span class="brace">{</span>
        <span class="punctuation">$</span>expr
    <span class="brace">}</span>
<span class="brace">}</span>

<span class="comment documentation">/// textually shadow previous definition</span>
<span class="keyword">macro_rules</span><span class="macro_bang">!</span> <span class="macro declaration public">noop</span> <span class="brace">{</span>
    <span class="parenthesis">(</span><span class="punctuation">$</span>expr<span class="colon">:</span>expr<span class="parenthesis">)</span> <span class="operator">=</span><span class="operator">&gt;</span> <span class="brace">{</span>
        <span class="punctuation">$</span>expr
    <span class="brace">}</span>
<span class="brace">}</span>

<span class="keyword">macro_rules</span><span class="macro_bang">!</span> <span class="macro declaration public">keyword_frag</span> <span class="brace">{</span>
    <span class="parenthesis">(</span><span class="punctuation">$</span>type<span class="colon">:</span>ty<span class="parenthesis">)</span> <span class="operator">=</span><span class="operator">&gt;</span> <span class="parenthesis">(</span><span class="punctuation">$</span>type<span class="parenthesis">)</span>
<span class="brace">}</span>

<span class="keyword">macro</span> <span class="macro declaration">with_args</span><span class="parenthesis">(</span><span class="punctuation">$</span>i<span class="colon">:</span>ident<span class="parenthesis">)</span> <span class="brace">{</span>
    <span class="punctuation">$</span>i
<span class="brace">}</span>

<span class="keyword">macro</span> <span class="macro declaration">without_args</span> <span class="brace">{</span>
    <span class="parenthesis">(</span><span class="punctuation">$</span>i<span class="colon">:</span>ident<span class="parenthesis">)</span> <span class="operator">=</span><span class="angle">&gt;</span> <span class="brace">{</span>
        <span class="punctuation">$</span>i
    <span class="brace">}</span>
<span class="brace">}</span>

<span class="keyword">macro_rules</span><span class="macro_bang">!</span> <span class="macro declaration public">id</span> <span class="brace">{</span>
    <span class="parenthesis">(</span><span class="punctuation">$</span><span class="parenthesis">(</span><span class="punctuation">$</span>tt<span class="colon">:</span>tt<span class="parenthesis">)</span><span class="punctuation">*</span><span class="parenthesis">)</span> <span class="operator">=</span><span class="operator">&gt;</span> <span class="brace">{</span>
        <span class="punctuation">$</span><span class="parenthesis">(</span><span class="punctuation">$</span>tt<span class="parenthesis">)</span><span class="punctuation">*</span>
    <span class="brace">}</span><span class="semicolon">;</span>
<span class="brace">}</span>

<span class="macro default_library library">include</span><span class="macro_bang">!</span><span class="parenthesis">(</span><span class="macro default_library library macro">concat</span><span class="macro_bang macro">!</span><span class="parenthesis macro">(</span><span class="string_literal macro">"foo/"</span><span class="comma macro">,</span> <span class="string_literal macro">"foo.rs"</span><span class="parenthesis macro">)</span><span class="parenthesis">)</span><span class="semicolon">;</span>

<span class="keyword">struct</span> <span class="struct declaration">S</span><span class="angle">&lt;</span><span class="type_param declaration">T</span><span class="angle">&gt;</span><span class="parenthesis">(</span><span class="type_param">T</span><span class="parenthesis">)</span><span class="semicolon">;</span>
<span class="keyword">fn</span> <span class="function declaration">main</span><span class="parenthesis">(</span><span class="parenthesis">)</span> <span class="brace">{</span>
    <span class="keyword">struct</span> <span class="struct declaration">TestLocal</span><span class="semicolon">;</span>
    <span class="comment">// regression test, TestLocal here used to not resolve</span>
    <span class="keyword">let</span> <span class="punctuation">_</span><span class="colon">:</span> <span class="struct">S</span><span class="angle">&lt;</span><span class="macro public">id</span><span class="macro_bang">!</span><span class="bracket">[</span><span class="struct macro">TestLocal</span><span class="bracket">]</span><span class="angle">&gt;</span><span class="semicolon">;</span>

    <span class="macro default_library library">format_args</span><span class="macro_bang">!</span><span class="parenthesis">(</span><span class="string_literal macro">"Hello, </span><span class="format_specifier">{</span><span class="format_specifier">}</span><span class="string_literal macro">!"</span><span class="comma macro">,</span> <span class="parenthesis macro">(</span><span class="numeric_literal macro">92</span><span class="comma macro">,</span><span class="parenthesis macro">)</span><span class="operator macro">.</span><span class="field library macro">0</span><span class="parenthesis">)</span><span class="semicolon">;</span>
    <span class="macro public">dont_color_me_braces</span><span class="macro_bang">!</span><span class="parenthesis">(</span><span class="parenthesis">)</span><span class="semicolon">;</span>
    <span class="macro public">noop</span><span class="macro_bang">!</span><span class="parenthesis">(</span><span class="macro macro public">noop</span><span class="macro_bang macro">!</span><span class="parenthesis macro">(</span><span class="numeric_literal macro">1</span><span class="parenthesis macro">)</span><span class="parenthesis">)</span><span class="semicolon">;</span>
<span class="brace">}</span>
</code></pre>